The present invention relates to a sealant and coating composition and pertains more particularly to curable one-part blocked isocyanate-terminated polymeric compositions that are useful as caulking sealants and coating compositions.
Sealant and coating compositions desirably have a combination of properties which render them particularly suitable for their intended applications. Such compositions should be able to be packaged in sealed containers or cartridges and stored for relatively long periods of time without objectionably "setting up" or hardening (as a result of cross-linking). When applied as a caulking sealant or coating composition, they should form a relatively tack-free surface soon after being applied and exposed to atmospheric moisture and should cure without the formation of bubbles within an acceptable time period. They should adhere tenaciously in the cured state to a wide variety of surfaces, such as to glass, aluminum, concrete, marble and steel surfaces. The sealant or coating in the cured state should have sufficient elasticity and flexibility to withstand expansions and contractions of panels, etc. with which it is associated during temperature variations experienced as a result of climatic changes and to withstand wind forces that cause panels with which it is associated to flex or twist.
Various sealant compositions have been proposed heretofore:
U.S. Pat. No. 3,248,371, the disclosure of which is incorporated herein by reference, is directed to a blocked isocyanate-terminated urethane coating composition formed by reacting an isocyanate-terminated polyether-based urethane intermediate with a hydroxy tertiary amine.
U.S. Pat. No. 3,267,078, the disclosure thereof being incorporated herein by reference, pertains to a coating composition that contains a blocked isocyanate-terminated polyether-based urethane intermediate and a diimine prepared by reacting a diamine with a carbonyl compound such as a ketone or aldehyde.
U.S. Pat. No. 3,445,436, the disclosure thereof being incorporated herein by reference, discloses polyurethane polyepoxide compositions formed by reacting a polyester or polyether triol, with or without a minor proportion of a diol material blended therewith, with a polyisocyanate to produce a liquid polyurethane prepolymer material, the liquid polyurethane prepolymer then being reacted with glycidol or a 2-alkyl glycidol (such as 2-methyl glycidol or 2-ethyl glycidol) to form the polyurethane polyepoxide. The polyurethane polyepoxide compositions can be cross-linked by the addition of an organic polyamine.
U.S. Pat. No. 3,627,722, the disclosure thereof being incorporated herein by reference, describes a sealant composition formed by the reaction of an isocyanate-terminated polyurethane prepolymer with a trialkyloxysilane such as N-methylaminopropyltrimethoxysilane.
U.S. Pat. No. 3,632,557, the disclosure thereof being incorporated herein by reference, discloses reacting an isocyanate-terminated polyurethane prepolymer with a trifunctional organosilicon compound such as gamma-aminopropyltrimethoxysilane. A stoichiometric excess of the aminosilane is used.
U.S. Pat. No. 3,309,261, the disclosure of which is incorporated herein by reference, discloses the addition of an aminosilane to a polyurethane adhesive to improve the adhesive's lap shear strength and peel strength.
U.S. Pat. No. 3,372,083, the disclosure thereof being incorporated herein by reference, describes the use of a bituminous material that has been reacted with a polyisocyanate in combination with a polyurethane prepolymer.
U.S. Pat. No. 4,067,844, the disclosure thereof being incorporated herein by reference, describes a one-part polyurethane sealant composition formed by preparing an isocyanate-terminated polyurethane prepolymer and then reacting a minor proportion of the NCO terminates with specified aminosilane materials or the reaction product of a mercaptosilane with a monoepoxide or the reaction product of an epoxysilane with a secondary amine.